Monday, June 04, 2007

I'm Back!

Thursday, August 24, 2006

Bye Bye Pluto (Finally)

Pluto and Charon, mutually attracted rocks, now called "dwarf planets."

I've been teaching Astronomy for four years, and every year I've told my students that Pluto should not be classified as a planet. Smaller than Earth's moon, it has none of the properties that would make it a true planet in terms of size and composition. Pluto's composition matters in terms of classification because of how the solar system formed (see previous post). There are terrestrial planets nearest the Sun and gaseous planets farther out. Pluto is one of thousands of rocks outside of this gas giant region, and should be grouped accordingly. Its orbit and location should put it in a class with other rocks called "Kuiper Belt Objects" in the outer reaches of the solar system. The only shame is that Pluto's orbit, although highly irregular when compared with the other eight planets, does happen to coincide with Neptune's every once in a while, so it is the closest of the K.B.O.'s. Hopefully this "controversy" will make people want to know more about the formation of the solar system, not less. This change reminds me of why I prefer Science to belief; we can change our minds when new evidence arrives. Thanks to Xena and Quaoar and all of the other big rocks out there!

Saturday, July 01, 2006

The CREATION of Earth

It should be the ACCRETION of Earth, but I was being flippant. If you still fear thunder and lightning, then having a god would make sense. Otherwise, the accretion of particles, pebbles, rocks, boulders, and mountains would make more sense if you considered the force of gravity. An atmosphere would follow, because even gas has gravity (and that's why I chose this particular photograph). And once you have an atmosphere, charges take sides and you get thunder and lightning. More to follow...

Sunday, February 12, 2006

How Solar Systems Form, Part I

Because of the recent discovery of hyperstar solar systems, I thought I should explain the current knowledge we have about solar system formation. In order to understand these structures, a basic knowledge of Newtonian gravitation is in order. Gravity is an attractive force, ruled by two distinct factors: mass and distance. Everything in the universe has mass, with the exception of exotic particles like bosons. Objects with mass are attracted to one another directly in proportion to their mass and indirectly to their distance. What this means is that the more massive something is, the more attractive its force in relation to other things. Conversely, if an object is more distant from another object, it has less of an attractive, gravitational force. On Earth, we do not sense this effect because humans are more attracted to Earth than they are to other people and things. If we were in space, away from gigantic celestial objects, we would be like magnets when it came to smaller things. Paperclips would gravitate toward us. On Earth, paperclips are as drawn to Earth as we are, but in space they would be attracted to the next, more massive thing.

The most abundant element in the universe is hydrogen, and in areas where there is more hydrogen atoms than not, they coalesce to form a protostar ("before or first" star). Like a toilet bowl, everything is drawn around the protostar, some falling into it and some having the mass and tangential velocity to stay in orbit. In the case of our own solar system, there were massive mountains of material called "planetessimals" that would attract to each other to create the inner planets. As the proto-Sun became more massive, and it acquired the gravity in its core to fuse hydrogen into helium, due to the tremendous pressures and temperatures acting on the core. Once fusion began, the Sun (now a "star," instead of a protostar) blew off its outer layer of hydrogen gas to form the outer gas giants, which had their own menial planetessimal cores with enough gravity to hang onto the excess gas.

New Mega Solar Systems Discovered

Two new solar systems have been detected around hyperstars thirty times more massive than our Sun. Resembling Saturn, these giant stars are surrounded by rings of debris, proving for the first time that planets can actually accrete around stars once thought too large to allow such formations. This discovery, along with the recent sighting of a planet only five times the size of Earth, proves once again that there are not only a nearly infinite numbers of stars in the universe, but also planets!

Sunday, January 15, 2006

Success!

We now interrupt this blog to report the successful return of Stardust. Back from a seven-year mission, Stardust is a capsule carrying cometary dust from Wild 2, an ineptly-named comet. Samples were taken from the comet's tail back in 2004, and analyzing the particles will shed new light on the formation of the early solar system. I suppose now is as good a time as any to explain what comets are and where they come from.

Out in the far reaches of the solar system there is a vast region of billions of chunks of ice ranging in size from pebbles to mountains. This region is known as the Oort Cloud, named after the Dutch astronomer, Jan Oort, who first proposed the existence of these icy objects 50,000 A.U.'s away from the Sun. (An A.U. is an astonomical unit; 1 A.U. = 93,000,000 miles or the distance from the Earth to the Sun). Because the rocks are so small and so far away, we cannot see them, but their existence can be inferred from the orbits of the comets that pass through our solar system every once in a while. As the comets get pulled out of the Oort Cloud due to random collisions or the gravitational tug of other stars, they get pulled in toward the gas giants and eventually toward our Sun. As the coma or body of the comet heats up, the ice melts and the comet acquires a tail of glowing (ionized) dust particles. Tails can stretch to distances up to 1,000,000 miles long! A beautiful sight indeed.

Thursday, January 05, 2006

Galileo Sees the Light, Again

The Milky Way was a mystery in Galileo's time. Greek mythology proposed that the band of clouds in the night sky was a remnant of Hera's breast milk strewn in an arc above the northern horizon (hence the "Milky" Way). When Galileo looked at our galaxy with his telescope he could easily see points of light that could only be too far away to have a parallax shift. Why would God create objects that humans couldn't resolve with their own eyes? Once again he was baffled by what he saw, and yet he saw the light.